Abstract: The extract from green peel of Juglans mandshurica Maxim. was extracted by common method for studying its allelopathy and analyzing the chemical components. Results showed that the alcohol extract and the ethyl acetate part of alcohol extract (separated with ethyl acetate from alcohol extract) exhibit allelopathy (inhibiting seed germination and seedling growth) on Brassica chinesis, Raphanus sativus and Medicago sativa. Their effects were extract-concentration dependent, increasing with the increase of extract concentration. The chemical components in the ethyl acetate part of alcohol extract from green peel of J. mandshurica were analyzed by GC-MS. Results showed that the main chemical components and their GC contents in the ethyl acetate part of alcohol extract were: 5-hydroxy-1,4-naphthalenedione(juglone) 31.20%, n-hexadecanoic acid 9.99%, 7-methoxy-1-tetralone 7.99%, 1,5-naphthalenediol 7.15%, 2,6-dimethoxy-phenol 4.36%, 4-butoxy benzaldehyde 3.23%, 5-(hydroxymethyl)-2-furancarboxaldehyde 2.96%,1,3-dihydroxyacetone dimmer 2.94%,glycerin 2.77%, 1(3H)-isobenzofuranone 2.57%. Twenty-four compounds in the ethyl acetate part of alcohol extract have been identified with total GC content of 94.55%.

Key words: green peel of Juglans mandshurica Maxim., allelopathy, component analysis